SOAPSTONE

( Fr- stéatite [= steatite]; Ger- Speckstein/Seifenstein; Nor- spekkstein; Rus- [= steatite] )

SOAPSTONE (=steatite)

A. Soapstone. Zimbabwe (formerly Rhodesia) carving (height - 8 cm). R.V. Dietrich collection. (© photo by Dick Dietrich)

B. Soapstone. Inuit carving (height - 12.5 cm). R.V. Dietrich collection. (© photo by Dick Dietrich)

C. Soapstone simulant. Pyrophyllite-rich rock, marketed as "South African Wonderstone," eagle (height - ca. 30 cm) sculpted by Dennis R. Christy. Ron Koch collection. (© photo by D.R. Christy)

DESCRIPTION: Soapstone is the name widely applied to a rock made up largely or wholly of the mineral talc - Mg₃Si₄O₁₀(OH)₂; some soapstones are micro- or cryptocrystalline. Properties of talc:
    Colors - white, gray, greenish gray, pale green -- commonly discolored in reddish or brownish hues and mottled
    H. 1 (but, because of the presence of impurities, effective hardness of soapstone may range up to 7)
    S.G. 2.5-2.8
    Light transmission - translucent to opaque
    Luster - waxy to pearly
    Miscellany - feels greasy or soapy.   Some soapstone contains noteworthy percentages of pyrophyllite, which is virtually indistinguishable from talc by macroscopic means. Other relatively common constituents of soapstone, which may or may not be macroscopically discernible, are chlorite, dolomite, magnesite, tremolite and minor amounts of oxides such as magnetite and chromite and even rare sulfides.

OTHER NAMES:

Agalmatolite - some agalmatolite is soapstone -- see Appendix A and pyrophyllite under SIMULANTS subtitle in this entry.
Combarbalite - name given to varicolored (e.g., diverse red, green, yellow, and brown hues) soapstone from vicinity of Combarbala in the Andean foothills of Coquimbo Province, Chile.
Gorara stone - ill-defined "soft stone" -- also referred to as India soapstone and sometimes, apparently incorrectly, as gorara marble -- reportedly from Hamipur and Mahoba areas of Uttar Pradesh, India; colors, commonly mottled, include gray, pink, green, tan and black.
Honan jade - a marketplace misnomer.
Image stone - name given to some steatite (see below) from India.
Manchurian jade - a marketplace misnomer.
Neolite - marketplace name once used for steatite.
Pagodaite - see Appendix A.
Palewa soapstone - tan, green, gray (which is darkened when hand polished) soapstone that has been carved for several decades in Agra, India, site of the famous Taj Mahal.
Pearlescent soapstone - vaguely descriptive designation given soapstones of diverse colors marketed as carved "bowls" made explicitly for aromatic and votive candles.
Potstone - a marketplace name applied to steatite, especially that fashioned into vessels for heating, for example, water for tea.
Pratima culler - name given to some steatite (see below) from India.
Rapoka - name given rock(s?), which are soapstone(like?), rather widely marketed as carvings fashioned in Zimbabwe. Some of the materials so-identified may be serpentine rather than soapstone.
Steatite - a widley used synonym of soapstone, as is indicated by the entry subtitle.
Suzhou jade - a marketplace misnomer.

Several other vernacular terms have been given soapstone because of certain appearances and uses -- e.g., bacon stone, grease stone and lard stone and image stone, figure stone and pot stone.

USES: For seals, especially in ancient times; more recently and currently, chiefly carvings --some as objets d'art, others for a variety of utilitarian articles such as soap dishes and incense burners. In addition, I have seen soapstones shaped to resemble beach stones for use as markers -- "Use your permanent paint marker to inscribe the plant's name, ..." for placing in appropriate places in gardens.

OCCURRENCES: Diverse -- e.g. as the result of metamorphism of sedimentary rocks, such as siliceous dolostones -- and relatively widely.

NOTEWORTHY LOCALITIES: Soapstone occurs in many metamorphic terranes throughout the world. Two well-known sources of soapstone used for carvings (etc.) are the Limbue quarries, near Lake Nyasa, Malawi (formerly Nyasaland) and quarries near Kundla, Gujarat State, Bombay Province, India. Soapstone for Canadian Eskimo carvings has come from the Yukon Territory and Baffin Island. In the western United States, perhaps the best known source of soapstone used for carvings (etc.) is Skagit County, Washington. Quarries near Schulyer, Nelson County, Virginia, which have been a good source of soapstone used for such things as griddles and acid-resistant counter tops and sinks, would appear to constitute a potential source of carving material.

REMARKS: The designation soapstone was apparently applied because the rock tends to feel greasy or soapy.

Soapstone, because it is easily carved, was sculpted into, for example, busts and fashioned into seals at least as early as 2550 B.C. Also, soapstone was early used for ornaments, tools and diverse containers such as bowls in what is now the state of Georgia, U.S.A. This latter use, which antedated use of pottery in the region, was especially important because the carved soapstone bowls etc. would transmit and retain heat without breaking and consequently could be used in cooking. Today, so-called soapstone carving kits, which include "pre-shaped blocks ... of beautiful Brazilian soapstone," are marketed for would-be sculptors.

Especially in the past, soapstone of high talc content has had several other interesting uses. A few examples are: as the pieces tailors used to mark clothing for alteration; as slate pencils; for bedwarmers and foot warmers in sleighs and automobiles (before the time of built-in heaters); [and] for the just mentioned acid-resistant soapstone counters and sinks, which were used for the most part in well equipped chemical laboratories. During World War II, talc was on the list of critical minerals because of its use in high-frequency insulators in such things as radios. Today, it continues to be used for such things as paper and paint fillers and for the production of talcum powder. And just a few years ago, when consulting for a soapstone producer, I was presented with a honed slab (with a handle on it) that was to be used as a griddle upon which, for example, eggs and pancakes could be grilled without using any grease. More recently, mitten shaped soapstone forms have been marketed rather widely as hand warmers and/or for warming mittens "before putting them on to wear out side on cold mornings."

SIMULANTS:

Pyrophyllites- diverse materials consisting largely of pyrophyllite have been given names such agalmatolite, koranna stone and South African wonderstone (see comments re the designation wonderstone that follow the Scenic sandstone listing under the OTHER NAMES subheading in the SANDSTONE entry). Pieces fashioned from this rock, a gemrock in its own right, are usually marketed along with and not distinguished from pieces fashioned from soapstone. Pyrophyllite-rich rocks, many of which are dark gray, slatelike rocks consist largely of pyrophyllite but also contain up to about 10 percent chloritoid or epidote and, in some cases other minerals such as rutile; they have been recovered and used from several localities -- e.g., China, Transvaal (South Africa) and North Carolina. - [likely to require non-macroscopic means].

REFERENCES: No general reference. Indian Bureau of Mines, 1992.

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